1. Field
A photoresist composition and a method for forming a metal pattern are provided. More particularly, a photoresist composition that may skip a vacuum conductive drying (VCD) process, when the photoresist composition is coated, and a method of forming a metal pattern are provided.
2. Description of the Related Art
Generally, a display substrate that is used for a display device includes a thin film transistor that serves as a switching element for driving a pixel unit, a signal line connected to the thin film transistor, and a pixel electrode. The signal line includes a gate line that provides a gate driving signal, and a data line that crosses the gate line and provides a data driving signal.
Generally, a photolithography process is used for forming the thin film transistor, the signal line and the pixel electrode. According to the photolithography process, a photoresist pattern is formed on an object layer, and the object layer is patterned by using the photoresist pattern as a mask to form a desired pattern.
According to a conventional process, a photoresist composition is coated on the object layer to form a coating layer, and the coating layer is exposed to a light by using a mask. A developing solution is then provided on the light-exposed coating layer to remove a portion of the light-exposed coating layer so as to form a photoresist pattern. Additionally, the coating layer is soft-baked before being exposed to light, and hard-baked after the developing solution is provided.
Recently, a slit coating process has become widely used for a liquid crystal display device because of the large scale of the circuit. The slit coating process needs a photoresist composition with a low viscosity. A photoresist composition having a low viscosity includes a large amount of a solvent, has and as a result such a photoresist composition, when spread, may have many stains that decrease the pattern uniformity. Accordingly, in order to solve the above-mentioned problem, a vacuum conductive drying (VCD) process is performed to reduce a solvent. However, pattern uniformity can also decrease because the pressure applied is not uniform. Furthermore, an upper photoresist pattern may have an inverse-taper wider than a lower photoresist pattern, because the surface of the layer is dried faster than the inside of the layer. Accordingly, a desired pattern is difficult to form.